Process of preparing india-rubber for vulcanization.



UNITED STATES HEINRICH PATENT OFFICE.

SGHOLZ, or BERLIN, GERMANY, ASSIGNOR To BERNIIARD GRATZ, or BERLIN,

' GERMANY.

PROCESS OF PRiEPAJRING INDIA-RUBBER FOR VULG'ANJEZATION.

Specification of Letters Patent.

Patented June 30,. mos.

Application filed February 27, 1906. Serial No. 303,217

To all whom it may concern:

Be it known that I, Hn'mnron SOHOLZ, a sub'cct of the King of Prussia, residin at Ber in, in the Kingdom of Prussia and aer- 5 man Empire, have invented certain new and useful Im rovements in Processes of. Preparing In which the following is a specification.

v For the purpose of vulcanization indiarubber, as is well-known, -is treated with sulfurat 130-4 50 re recs centigrade. The product is only perl ectly homogeneous in structure, if the rubber was altogether free from resin. Inthe rubber industry, however, the best washed rubber. always contains some 1 to 20 per centof resinous, oily or waxy, matter, This melts atthc. vulcanizing'temperature (130-150 cent), and in-the melted condition likewise absorbs sulfur, causing a disturbin reaction,which affects the homogeneity o the vulcanized rubber. These inconveniences can be entirely overcome by means of the present invention.

According to my invention the rubber to be vulcanized is specially sulfur treatment by bein eed from those in redients which inter ere with pro or vu canization. For this pur ose the rub er (which'if dirt should be rst thoroughly cleaned in wel-known manner) is treated preferably with hot resin-solvents which behave indifferently or neutrally in regard to rubber (such as glacial acetic acid, or amyl alcohol, or other alcohols, or acetone), after which the rubber is washed and dried, and then vulcanized in the usual manner, The vulcanization of such resin-free rubber procoeds rapidly without any disturb reaction, and the product is of a pe ectly 40 homogeneous character.

.- The treatment of'the impure rubber may la-Rubber for Vulcanization, of

prepared for the be carried on exceedingly rapidly and to great advantage, if laoial acetic acidor alnyl alcohol is einp eyed: If urc amy'l alcohol is used in boilin condition, it dissolves the resin. very rapi 1y, but at the high temperature (130-140 degrees cent.) which 'is very near the melting-point of rubi'icnit will seriously attack the latter. In order to avoid this, the temperature shoahi. be to kept so low. as not to affect the rubber. This may be done by adding water-t0 the amyi alcohol, whereby in boiling with the aid of a reflux-cooler the temperature is mein iced at 100 cent. owin to the presence of water Since amyl alcoho i does not dissolve water, the addition of water is harmi and the solvent ca acity of the alcohol 3142!. ii- Ininished by tie water. The resins be separated from the itII-Zlti alcohol by he ling:

w th steam, the alcohol passing eve; with the latter and separating from the water in the receiver, as it does not mix with water. The resins remain behind in the still. This method of separation has the advanta e over simple distillation, that the resins 0 not suffer by the high boiling-temperature.

What I do claim as my invention'and desire to secure by Letters Patent, is-

The method of preparing rubber for'vuL 7o canization consistin in boiling the rubber with am 1 alcohol with the simultaneous ad dition 0 water thereby keeping down the temperature below the melting point of the rubber. I I

In testimony whereof I have attired my signature in presence of two witnessesi- HEINRICH SCHOLZ.

, Witnesses:

BERNHARD GRATZ, KARL GARZ. 

